"Oblique cone" - pros and cons?

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graaf

graaf

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Joined 2007
#1

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#3
the idea seems to be to make the soundwave reach the surround not simultaneously along all radiuses but at slightly different times due to uneven path lengths thanks to cone asymmetry

I wonder if the same effect could be achieved by applying a kind of asymmetrical pattern treatment to a paper cone making the sound wave travel slightly faster/slower along different radiuses?
 
#6
I think if one looks at the data shown in the links of the first post, it is clear they want to eliminate the breakup mode. I'm not sure whether the intention as to use mass off-setting or not. The concept of shape off-set seems more adequate with domes rather than cones.
 
#8
Not really a new idea, Yamaha did something very like this with their ear-shaped woofer way back.
Never get a chance to listen to that one every time they come up on E*** there is stiff competition and heavy bidding, so the question is " Does it work" ??
 
#9
As I recall the 'ear speaker' was more a coil driven tensioned membrane without a true surround. The intent here seems to distribute the cone face's standing waves in frequency. Either it's advances in finite element modeling ushering a new paradigm in speakers or another short lived marketing fad that leaves no residue, like 'ear speakers'. 🙂
 
#10
Cal Weldon said:
What interests me is why you would consider offsetting the mass of the cone.
Click to expand...

Hi Cal!
It's the alternative solution to making the damped, spring-loaded mass intrinsically perfect. Instead, you embrace and nurture the resonances. You want an infinite number of them so that the response becomes flat because every frequency is equally resonant. I think the key phrase is "..in the limit..."

NXT has a technology that uses this principal too. They have a piezzo (I believe) transducer that you can slap on any old plastic surface to make a speaker. The trick is finding the stimulation point that enables the greatest number of nodes.

Statistically, it's fantastic
😉
 
#13
planet10 said:


My initial thot as well.

dave
Click to expand...

but where are high quality elliptical speakers? 🙁

what about something that can be done DIY-way that is appropriate treatment (using asymmetrical pattern) of a paper cone?

I have Visaton B200 and two kinds of cone treatment liquids from Intertechnik - Stabilon (stiffener) and Vinylflex (dampener)

so I am thinking whether it could work and what pattern would be optimal

best regards!
graaf
 
#14
Funny looking thing!

Isn't this what Graham M has been telling us? That the oval cones don't have the same nasty breakup modes?

Oh yeah, I'm with Ian on this one. Made me think of the NXT stuff straight away.
 
#16
I do a similar thing with asymmetrical soundboards on guitars, to increase the radiation efficiency of the resonances.

Symmetric modes have lower radiation efficiency because they can cancel.
Some low microphonic tubes have symmetric anodes for the same reason.

I don`t think asymmetrical loudspeaker cones is a good idea at all.
Oval or elliptic will not do the same thing, as the modes are still symmetric.
 
#20
graaf said:


what about the measurement attached to the first post and showing obvious DECREASE of cone resonance?

is it fake?

best!
graaf
Click to expand...

I could be wrong...

If it is fake or not, I dont know, it might be. It is possible it doesn`t show the whole picture. In marketing anything is possible.
The response might change at higher spl as the uneven mass and air load probably makes it wobble.

If it is real.... The red line shows one large very bad resonance, but also a smoother response in the rest of the range. The better high frequency extension of the blue line could be a result of resonances.
It would be interesting to se impedance plots too.
 
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